Telescopes

1. Telescopes Donna Kubik PHYS162 Spring, 2006

2. Purpose of telescopes To do what our eyes cannot Collect photons (from radio to gamma ray) Achieve higher resolution Record the received photons Images Spectra

3. Recording Rarely are your eyes used to directly look through a telescope, even for an optical telescope!

4. Types of EM radiation Astronomers have constructed telescopes that have detected all forms of EM radiation, both visible and non-visible, emitted by objects in space.

5. Types of EM radiation Radio Millimeter Sub-millimeter Infrared Optical Ultraviolet Xray Gamma ray

6. Types of astronomers Radio astronomers Millimeter astronomers Sub-millimeter astronomers Infrared astronomers Optical astronomers Ultraviolet astronomers X-ray astronomers Gamma ray astronomers

7. Types of astronomy Radio astronomy Millimeter astronomy Sub-millimeter astronomy Infrared astronomy Optical astronomy Ultraviolet astronomy X-ray astronomy Gamma ray astronomy

8. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

9. The telescopes look very different! Effelsberg radio telescope, Germany

10. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

11. The telescopes look very different! NRAO 12 meter telescope, Kitt Peak Observatory

12. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

13. The telescopes look very different! Sub Millimeter Telescope (SMT), Mt. Graham, AZ

14. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

15. The telescopes look very different! SIRTF Space Infra Red Telescope Facility

16. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

17. The telescopes look very different! Yerkes 40-inch telescope, Williams Bay, WI World’s largest refractor

18. The telescopes look very different! KPNO Kitt Peak National Observatory 2.1 meter telescope

19. The telescopes look very different! Keck optical telescopes Mauna Kea, Hawaii

20. The telescopes look very different! HST Hubble Space Telescope

21. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

22. The telescopes look very different! HUT Hopkins Ultraviolet Telescope

23. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

24. The telescopes look very different! XMM Xray MultiMirror telescope

25. Types of telescopes Radio telescopes Millimeter telescopes Sub-millimeter telescopes Infrared telescope Optical telescopes Ultraviolet telescopes X-ray telescopes Gamma ray telescopes

26. The telescopes look very different! CGRO Compton Gamma Ray Observatory

27. And….. the images from the different types of telescopes look very different!

28. The images look very different Ultraviolet Visible Infrared NGC1512 barred spiral galaxy HST images

29. The images look very different M87 giant elliptical galaxy in Virgo cluster

30. The images look very different X-ray (Chandra) Radio Cygnus A

31. The images look very different 30 Doradus Open cluster in LMC red=xray green=optical blue=UV

32. Types of EM radiation Why do the telescopes and images look so different?

33. Types of EM radiation The difference between each type of EM radiation in each region is its energy!

34. Types of EM radiation Because of their different energies, each type of EM radiation interacts differently with matter. That’s why the telescopes look so different. That’s why the images look so different. And that’s also why the telescopes are located at very different places...

35. Types of EM radiation The energy (or freq or wavelength) determines how the radiation will react with the atmosphere.

36. Atmospheric windows Radio, millimeter, sub-millimeter Infrared and optical Ultraviolet xrays, gamma rays Ozone and oxygen Water and CO2

37. Location of radio, millimeter, and sub-millimeter telescopes Radio Ground-based Millimeter wave High and dry Sub-millimeter Even higher and drier

38. Location of infrared and optical telescopes Infrared High and dry Optical Ground-based

39. Location of ultraviolet, xray, and gamma ray telescopes Ultraviolet Space Xray Space Gamma ray Ground-based and Space

40. Types of EM radiation Astronomers often group the different types of EM radiation into 3 groups according to their energy.

41. Types of EM radiation Low frequency/long wavelength LOW ENERGY Radio Millimeter Sub-millimeter Mid frequency/mid wavelength MID ENERGY Infrared Optical High frequency/short wavelength HIGH ENERGY Ultraviolet X-ray Gamma ray

42. Types of telescopes For each energy range, we’ll discuss: Single telescopes Interferometers More than one telescope linked together

43. Types of EM radiation Low frequency/long wavelength LOW ENERGY Radio Millimeter Sub-millimeter Mid frequency/mid wavelength MID ENERGY Infrared Optical High frequency/short wavelength HIGH ENERGY Ultraviolet X-ray Gamma ray

44. Radio, millimeter, and submillimeter astronomy The place of radio, millimeter, and submillimeter astronomy the study of astronomy The parts of a radio telescope and how it works The two big challenges of radio astronomy overcome by radio astronomers Tiny signal strength of radio signals Low angular resolution Next generation radio, millimeter, and submillimeter telescopes

45. Low energy EM radiation

46. Discovery of CMB Arno Penzias and Robert Wilson (1965)

47. Discovery of pulsars Jocelyn Bell and 81.5 MHz radio telescope (1967)

48. Sources of radio, millimeter, and sub-millimeter radiation HII regions Synchrotron radiation Interstellar atoms and molecules Pulsars, quasars, radio galaxies Cosmic microwave background

49. Carl Jansky’s telescope Jansky's vertically polarized beam antenna was built in 1931 to study the direction of thunderstorms, which were suspected to cause signal-to-noise problems in Bell Lab’s initial transoceanic radio-telephone circuits. In addition to detecting lightning, Jansky detected a signal that that appeared 4 minutes earlier each day and was strongest when Sagittarius was high in the sky. The center of the Galaxy is in the direction of Sagittarius, so Jansky concluded that he was detecting radio waves from an astronomical source

50. Grote Reber’s telescope Grote Reber read about Jansky's discovery. In 1937, Reber built his own 32-foot-diameter parabolic dish antenna in his backyard in Wheaton, Illinois to seek cosmic radio emissions.